1. Field of the Invention
The present invention relates to a RJ modular connector, and more particularly to a RJ modular connector having a substrate provided therein to balance electrical couplings between terminals.
2. Description of the Related Art
RJ modular connector has been widely used in telecommunication system since it was firstly created. A so-called RJ45 modular connector has been widely used in the network system.
The RJ45 modular connector includes a total of eight terminals. Resulting from miniaturization of the computer, all corresponding components, including connectors, have to be reduced for their dimension and size. One of the negative consequences or problem created from miniaturization is electrical coupling between terminals. When the RJ connector is used in low speed signal transmission, the couplings between adjacent terminals can be ignored in light of its effect. However, when the RJ connector is used for high speed signal transmission, the couplings between adjacent terminals create a great problem. Unless the electrical coupling can be effectively controlled within an accepted level, it is unlikely that the RJ 45 modular connector can be used in the high-speed signal transmission.
One of the approaches is to select a pair of terminals as a differential pair. In the differential pair, two terminals transmit the same signal but with inverted phase. By this arrangement, the couplings coupled thereto can be finally subtracted in a data processing unit.
As known to one of ordinary skilled in the pertinent art that there are at least eight different patterns in selecting terminals as differential pair, i.e. T568A, T568B, USOC 4-pair, USOC 1-, 2- or 3-pair, 10BASE-T (802.3), Token Ring (802.5), 3-pair (MMJ), and TP-PMD (X3T9.5) and ATM. In each implementation, two terminals are selected as a pair in which some are close to each other, while some are apart from each other. Each pattern has its own uniqueness, while each also carries with it a coupling issue to be addressed.
Among those patterns, T568A and T568B are widely used and in T568A, terminals 1, 2 configure 3rd pair, terminals 3, 6 configure 2nd pair, terminals 4, 5 configure 1st pair while terminals 7, 8 configure 4th pair. In T568B, terminals 1, 2 configure 2nd pair, terminals 3, 6 configure 3rd pair, terminals 4, 5 configure 1st pair, while terminals 7, 8 configure 4th pair.
Since those eight terminals are equally spaced, electrical couplings between terminals will surely create some problems, i.e. coupling or cross-talk. For example, if we take terminal 3 into consideration, terminal 3 will naturally pick up energy coupled from terminals 2 and 4 which are close to terminal 3. On the other hand, terminal 6, which carries signal having inverted phase of the signal carried by terminal 3, will also pick up energy coupled from terminals 5 and 7. However, energy coupled into terminals 3, 6 from terminals 2 and 7 can not be suitably eliminated because terminals 3, 6 is unlikely to establish couplings between terminal 1 and terminal 8 to balance the couplings between terminals 2, 3 and 6, 7. Accordingly, signals transmitted by terminals 3, 6 carry noises generated by their adjacent terminals 2, 7. In addition, terminals 3 and 6 will also carry noises coupled thereto from terminals 4, 5 and which couplings should be also carefully taken care of in order to avoid certain noises.
In order to decrease the effects of electrical coupling between the (3rd, 4th) and (3rd, 2nd) terminals, and (6th, 5th) and (6th, 7th) terminals, many approaches have been provided, such as creating electrical couplings between 3rd and 1st terminals and 3rd and 5th terminals to balance the electrical coupling between the 3rd and 2nd terminals and 3rd and 4th terminals, and creating electrical coupling between 6th and 8th terminals and 6th and 4th terminals to balance the electrical couplings between the 6th and 7th terminals and 6th and 5th terminals.
However, as mentioned above, those eight terminals are arranged in a common plane, it is impossible to create those balancing electrical couplings, i.e. (1st, 3rd), (3rd, 5th), and (4th, 6th), (6th, 8th) terminals when all terminals are located in the same level, it is unlikely to create any electrical channels therebetween to create those electrical couplings accordingly.
The Siemon Company, a US company, discloses a solution posted on the Internet, http://www.siemon.com/white_papers/99-08-30-through-hole.asp. A hard copy thereof is herein attached for reference.
As clearly shown in FIG. 4 of that reference, 6th and 2nd terminals are arranged in the first layer, while 8th, 5th, 4th, and 1st terminals are arranged in the second layer, and 7th and 3rd terminals are arranged in the third layer.
The 6th terminal in the first layer has a rectangular loop having its longitudinal sides aligned with terminals 4th and 8th located in the second layer, while terminal 3 in the third layer also has a rectangular loop having its longitudinal sides aligned with terminals 5th and 1st located in the second layer.
In addition, the right longitudinal loop side of the terminal 6th further includes a square corresponding to a square formed in terminal 4th. The left longitudinal loop side of the terminal 3 includes also a square with respect to the square formed on terminal 8th.
Arrangements suggested by Siemon are to increase the couplings between (1st, 3rd), (3rd, 5th), and (4th, 6th), (6th, 8th) terminals thereby helping to balance electrical couplings of the terminals.
However, those eight or four set sets of terminals are arranged in three different layers, and each set of terminals are separately divided by an insulative sheet material. This will no doubt increase the complexity of the connector.
In addition, there are five different shapes and configurations among those eight terminals. Each terminal has its own shape which is different from each other, especially the 3rd and 6th terminals, each including the rectangular loop portion which overlaps corresponding terminals to create desired electrical couplings. Each loop further forms the square to increase the electrical couplings with corresponding terminals having the square. The electrical couplings created can help to meet higher system requirement. The eight different configuration of the terminals will surely increase the difficulty and complexity in production.
There are some other approaches, including routing terminal tails of those 3rd, 6th and 4th, 5th terminals to alter their position and affect couplings between 3rd, 2nd and 3rd, 4th; and 6th, 5th, and 6th, 7th terminals. However routing terminal tails will inevitably increase the manufacturing cost.
U.S. Pat. No. 6,120,329, issued to Steinman on Sep. 19, 2000, discloses another approach to solve the above-addressed problem. Again, terminals are configured with different shapes and dimensions making the production complex.
U.S. Pat. No. 5,069,641 issued to Sakamoto et al. discloses a suggestion of using printed circuit board in the RJ modular housing, however, it addresses different issues.
It is an object of this invention to provide an RJ modular connector, and more particularly to an RJ modular connector having a substrate with conductive traces provided therein to balance electrical couplings between terminals.
It is still an object of this invention to provide a RJ modular connector which can be easily manufactured.
In order to achieve the objective set forth, an RJ modular connector in accordance with the present invention comprises a housing defining a plug receiving section, and a terminal core receiving section. A terminal core is received in the terminal core receiving section and includes a plurality of terminals. A first and a second substrates are provided having first and second conductive traces thereon, respectively. The terminals are securely mounted onto the substrates. A first and a second electrical connections are established between a first and a second terminals and the first and second conductive traces, and a portion of each conductive trace is arranged to create a first and a second electrical couplings between the first and second terminals and a third and a fourth terminals, respectively. The third and the fourth terminals are arranged between the first and the second terminals and configure a differential pair located far from the first and the second terminals.
Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings.